Microsoft Security Essentials not starting.

I have a windows 7 laptop and have windows security essentials installed as an AV.

It has started (actually some time ago) to start up with security essentials in a stopped state, meaning I have to start it manually in the interface.

Fearing a virus have performed a full virus scan (both security essentials and a scan from a boot disk with an up-to-date copy of clamAV) which found nothing. Fearing a corrupt install I tried reinstalling security essentials and this has made no difference.

There is no other odd behaviour and no suspicious processes or network traffic, so I think I am clean.

There is an option to turn on real time protection which is ticked, but no other option (that I can see) that would suggest it should be off on startup. So anyone know what else I can try? it starting to get annoying.

Is it not starting, or is it starting but not displaying the icon in the system tray?

Is it set to start automatically in the Services display? - type services.msc in the Start search box, check Microsoft Antimalware entry.

the systray item is starting, but the icon is a red house with a cross in it, and the system messages tray icon pops up warning that security essentials is off. I open the interface and it says security essentials is stopped. The button that normally says "scan now" says "start" clicking on that and it all goes green again.

That process is getting to be a tedious habit when starting my laptop.

Alas I am far less familiar with windows and microsoft products now than I used to be (hence asking for help with what I hope is a simple problem to fix that is just escaping me right now)

I've got a recollection of having a similar problem in the past but can't recall the details. I do know that on occasion MSE plays silly b's and I just uninstall and re-install it, though haven't needed to for some time now.

Is this of any help?